Opposed piston engine

ABSTRACT

A two-stroke opposed piston engine is provided embodying a single crankshaft which is rotated by the conjoint action of opposed pistons acting through connecting rods and eccentrics on the crankshaft. The crankshaft and its eccentrics are relatively small as compared with those used in conventional internal combustion engines, and are so located in this engine that the forces of compression and the resultant torque are confined within a central area, and the need for a cylinder block of large mass or weight is eliminated. The engine does not require fans or blowers for scavenging the burned gases from the engine. In a modification of the engine, novel means for injecting fuel, a cooling fluid, or a mixture of these into the combustion chamber is employed.

iclttite States Patent 1 Herbert OPPOSED PISTON ENGINE William B.Herbert, 111 Yantacow Brook Rd., Upper Montclair, NJ. 07043 ;l2] Filed:Sept. 10, 1973 til] Appl. No.: 395,751

[76] Inventor:

[ Feb. 18., 1975 3,077,188 2/1963 Herrmann 123/74 A X PrimaryExaminer-Wendell E. Burns Attorney, Agent, or Firmlsler and OrnsteinABSTRACT A two-stroke opposed piston engine is provided embodying asingle crankshaft which is rotated by the conjoint action of opposedpistons acting through connecting rods and eccentrics on the crankshaft.The crankshaft and its eccentrics are relatively small as compared withthose used in conventional internal combustion engines, and are solocated in this engine that the forces of compression and the resultanttorque are confined within a central area, and the need for a cylinderblock of large mass or weight is eliminated. The engine does not requirefans or blowers for scavenging the burned gases from the engine. In amodification of the engine, novel means for injecting fuel, a coolingfluid, or a mixture of these into the combustion chamber is employed.

5 Claims, 12 Drawing Figures PAIENTEU EM Y 3,866.581

' SHEET 10F 6 4 26b 45 I9 4| 4e 42 56 arm 55 I4 260 fig, 4

PATENTEU 1 3,866,581 SHEET 6 OF 6 OPPOSED PISTON ENGINE This inventionrelates generally to internal combustion engines, which may be of thediesel or petrol (gasoline) type, but has reference more particularly totwostroke engines.

In two-stroke engines, two strokes of the engine are required to performa full cycle of operations, that is to say, changing the contents of thecylinder and effecting the combustion.

In conventional engines of the two stroke type, the forces ofcompression and the resultant torque transmitted to the crankshaft byconnecting rods are not confined within a central area, so that it isnecessary to provide a large cylinder block for such engines, therebyadding greatly to the mass and weight of the engine.

Another objection to such engines is that all or most of the inertialforces which aregenerated during the operation of the engine aretransmitted in a single or generally single direction, therebycontributing to the wear and tear on the engine, and increasing thevibra tion of the engine when in operation.

Other objections to such engines is .that they usually requirecompressors or blowers to scavenge the burned gases from the engine,thereby adding materially to the cost of the engine.

The present invention has, as its primary object, the provision of anopposed piston two-stroke engine of high efficiency which has embodiedtherein a single crankshaft, instead of multiple crankshafts, gears,levers, etc., which are usually associated with the use of opposedpistons.

Another object of the invention is to provide an opposed piston entingof the character described, in which the piston speeds are low incomparison with those of conventional engines, and in which thecrankshafts are smaller than in conventional engines, that is to say,the crankshaft throws are smaller.

Another object of the invention is to provide anopposed pistontwo-stroke engine of the character described, in which the forces ofcompression and the resultant torque transmitted to the shaft by theconnecting rods are confined within a central area, and the need for acylinder block of large mass or weight is eliminated.

Another object of the invention is to provide an engine of the characterdescribed, in which there is provided for each movement of eachcomponent part, an equal movement in the opposite direction, whereby acomplete offsetting or balancing of any and all inertial forces iseffected, with the single exception of the rotating torque, therebyreducing wear and tear of the engine, and reducing the vibration of theengine when in operation.

A further object of the invention is to provide an engine of thecharacter described, in which fans or other scavenging means arenot'required to scavenge the burned gases from the engine, and the.overall cost of the engine is thereby appreciably lowered.

A still further object of the invention is to provide an engine of thecharacter described,,embodying novel I apparent during the course of thefollowing description.

In the accompanying drawings forming a part of this specification, andin which like numerals are employed to designate like parts throughoutthe same,

FIG. 1 is a top plan view of an opposed piston engine embodying theinvention;

FIG. 2 is a front elevational view of the engine of FIG. 1;

FIG. 3 is an end elevational view of the engine, as viewed from theright end of FIG. 2;

FIG. 4 is a cross-sectional view, taken on the line 4-4 of FIG. 2;

FIG. 5 is a cross-sectional view, taken on the line 55 of FIG. 1;

FIG. 6 is a cross-sectional view, taken on the line 6-6 of FIG. 2;

FIG. 7 is a cross-sectional view, taken on the line 7 7 of FIG. 1;

FIG. 8 is a fragmentary cross-sectional view of a portion of FIG. 5, butwith the pistons in extended position;

FIG. 9 is a fragmentary cross-sectional view, on a greatly enlargedscale, of one of the check valves shown in FIG. 5;

FIG. 10 is a view similar to FIG. 1, but showing a modification of theengine, in which fuel, or water or other suitable fluid for lowering thecombustion temperature and reducing nitrogent emissions may be injectedinto the combustion chambers 1419;

FIG. 11 is a cross-sectional view, taken on the line ll-ll of FIG. 10,and

FIG. 12 is a cross-sectional view. taken on the line l2-l2 of FIG. 10.

Referring more particularly to FIGS. 1 to 9 of the drawings, referencenumerals 1(1 and 11 designate a pair of housings, which are secured inopposed rela tionship to each other, as best shown in FIGS. 1 and 2.

The housing 10 is provided with a cylindrical extension 12, while thehousing 11 is provided with a cylindrical extension 13, which is alignedaxially with the extension 12, but extends in a direction opposite tothat of the extension 12.

The housing 10 is hollowed out to provide a combustion chamber 14,defined by top and bottom walls 15 and 16 respectively, and end walls.17 and 18, which in terconnect the walls 15 and 16.

The housing 11 is similarly hollowed out to provide a combustion chamber19, defined by top and bottom walls 20 and 21 respectively, and endwalls 22 and 23 which interconnect the walls 20 and 21.

The chambers 14 and 19 coact to form a single combustion chamber in thecentral portion of the engine.

Secured to the housings l0 and 11, as by means of bolts 24, is a bearing25 which extends upwardly'into the space between the housings, and hasjournalled for rotation therein a crankshaft 26, the axis of whichintersects the axes of the cylindrical extensions 12 and 13. Thecrankshaft 26 is provided at opposite sides of the housings l0 and 11with eccentrics 26a, 26b, 26c and 26a.

The cylindrical extension 12 has secured to its outer end, a secondcylinder 27 of enlarged diameter, which is closed at its outer end by acover plate 29, which is secured to the cylinder 27. The plate 29 isprovided with a reed valve 30.

The cylindrical extension 13 has secured to its outer end a secondcylinder 31 of enlarged diameter, which is closed at its outer end by acover plate 33, which is secured to the cylinder 31. The plate 33 isprovided with a reed valve 34.

The cylindrical extension 12 has mounted therein, for sliding reciprocalmovement, a piston 35, having an enlarged head 35a which is slidable inthe cylinder 27.

The cylindrical extension 13 has mounted therein, for sliding reciprocalmovement, a piston 37 having an enlarged head 37a which is slidable inthe cylinder 31.

The piston 35 is provided with a-piston pin38 which extendsdiametricallythrough the piston, with the ends of the pin passingthrough slots 39 and 40in the sides of the cylindrical extension 12.

The piston 37 is provided with a piston pin 41 which extendsdiametrically through the piston, with the ends of the pin passingthrough slots 41 and 43 in the sides of the cylindrical extension 13.

One end of the piston pin 38 is pivotally connected to. one end of aconnecting rod or crank 44 provided at its opposite end with a circularopening 45 in which the eccentric 26b is mounted or disposed.

The other end of the piston pin 38 is pivotally connected to one end ofa connecting rod or crank 46 provided at its opposite end with acircular opening 47 in which the eccentric 260 is mounted or disposed.

One end of the piston pin 41 is pivotally connected to one end of aconnecting rod or crank 48 provided at its'opposite end with a circularopening 49 in which the eccentric 26a is mounted or disposed.

The other end of the piston 41 is pivotally connected to one end of aconnecting rod or crank 50 provided at its opposite end with a circularopening 51, in which the eccentric 26d is mounted or disposed.

The crankshaft 26 has keyed to one end thereof a flywheel 52 The portionof the cylinder 27 to the left of the piston head 35a, as viewed inFIGS. 4, and 8, may be considered as a compression intake chamber 53,while the portion ofthe cylinder 27 to the right of the piston head 35a,as viewed in FIGS. 4, 5 and 8, may be considered as a scavenging andair'super charging chamber 54.

Similarly, the portion of the cylinder 31 to the right of the pistonhead 37a, as viewed in FIGS. 4 and 5, may be considered as a compressionintake chamber 55, while the portion of the cylinder 31 to the left ofthe piston head 37a, as viewed in FIGS. 4 and 5, may be considered as ascavenging and air super charging chamber 56. I

As best seen in FIGS. 5, 6 and 9, the cylindrical extension 13 isprovided with a passageway 57, which is normally closed at its right endby a check valve comprising a ball 58, a coil spring 59, and a retainercap 60, which is screwed into the housing 10, and hascircumferentially-spaced openings 61 adapted to communicate thecombustion chamber 14 with the passageway 57 when the valve is open.

The passageway 57 communicates at its left end with a passageway 62 inthe cylinder 27, which is in axial alignment with the passageway 57. Thehead 35a of the piston 35 is provided with a passageway 63 which isnormally closed by a check valve generally designated by numeral 64,which is similar in construction to the check valve 58-59-60.

An intake port or passageway 65 extends from the passageway 59 to theinterior of the cylindrical extension 12.

An exhuast port 66 is provided, which extends from the interior of thecylindrical extension 12 to the atmosphere.

The cylindrical extension 13 is provided with a passageway 67, which isnormally closed at its left end by a check valve generally designated bynumeral 68, which is similar in all respects to the check valve58-59-60. 7

The passageway 67 communicates at its right end with a passageway 69 inthe cylinder 31, which is in axial alignment with the passageway 67. Thehead 37a of the piston 37 is provided with a passageway 70 which isnormally closed by a check valve generally designated by numeral 71which is similar in all respects to the check valve 58-59-60.

An intake port or passageway 72 extends from the passageway 67 to theinterior of the cylindrical extension 13.

An exhaust port 73 is provided which extends from the interior of thecylindrical extension 13 to the atmosphere.

The reed valve 30, as best seen in FIGS. 1, 2, 4 and 5, comprises acircular disk 74, which is secured to the cover plate 29 and is providedwith circumferentiallyspaced openings 75, which communicate with a bore76 in the cover plate, which, in turn, is provided with a valve seat 77.The valve is normally closed by a valve 78 having a stem 79 which passesaxially through the disk 74 and terminates in a head 80. A coil spring81 is interposed between the head and disk 74, and bithe valve to closedposition.

The reed valve 34 is of the same construction as the reed valve 30, andneed not, therefore. be described in detail.

Passageways 82, 83, 84 and 85 extend through the housings 10'and 11, andare provided for the purpose of circulating a cooling fluidtherethrough.

Passageways 86 are also provided in the housings 10 and 11 for thepassage therethrough of bolts (not shown), whereby the housings may besecured to each other by means of nuts and bolts.

An opening 87 is also provided which communicates with the combustionchamber 14-19, and serves for the introduction of fuel, when the engineis used as a diesel engine, or for a spark plug, when the engine is usedas a gasoline or spark ignition engine, in which latter case, a secondopening, not shown, may be used for the introduction of fuel into thecombustion chamber 14-19.

The bearing 25 may be provided with passageways 88 for the purpose ofcirculating a cooling fluid through the bearing.

The operation of the engine may now be briefly described.

The shaft 26 is shown in FIGS. 1, 2, 3, 4, 5 and 6, as at what may betermed the top dead center position, a position which corresponds to thetop of the piston stroke in a conventional internal combustion engine,and from which continued motion of the engine causes the piston todescend in such a conventional engine.

Rotation of the shaft 26 has brought the pistons 35 and 37 to such topdead center position, and has simultaneously induced atmospheric airthrough the valves 30 and 34 and into the intake chambers 53 and 55.

At this point, combustion of gases in the combustion chamber 14-19 iseffected, so that the pressure of the expanding gases in this chamber isexerted on the inner ends of the pistons 35 and 37, causing the shaft 26to rotate 180 beyond the top dead center position, and thereby cause theair charge in chambers 53 and 55 to be transferred through the checkvalves 64 and 71 and into chambers 54 and 56, which are created by theoutward movement of the pistons 35 and 37, the outermost position of thepiston 35 being shown in FIG. 8. Due to the relative sizes of thechambers 53 and 55, as compared with the chambers 54 and 56, the air inchambers 54 and 56 is under compression. When pistons 35 and 37 haveuncovered inlets 65 and 72 respectively, air from chambers 54 and 56enters combustion chamber 14-19 and cylinders 12 and 13 for scavenging.The pressure of the air in chambers 54 and 56 is reduced to atmosphericpressure.

Continued rotation of the shaft 26 through another 90 causes the aircharges in chambers 54 and 56 to be compressed, and further rotation ofthe shaft 26 through another 90, that is to say, back to the top deadcenter position, will cause super charging of the combustion area 14-19by the remaining charge of air from the chambers 54 and 56.

Where the engine is used as a diesel engine, suitable fuel injection iseffected through the opening 87, or, if the engine is to be used in themanner of a conventinal gasoline engine, as by a spark plug secured inthe opening 87.

The intake ports 65 and 72, and exhaust ports 66 and 73 are so locatedalong the cylindrical extensions 12 and 13, as to be effectively openedand closed by the movement of the pistons 35 and 37.

The mechanical connection of the pistons 35 and 37 with the crankshaft26 is, as described, effected through the piston pins 38 and 41, andconnecting rods 48, 44, 46 and 50, theslots 39, 40, 42 and 43 in thewalls of the cylindrical extensions 12 and 13 permitting suitablemovement to accommodate the stroke of the pistons.

The sequence of operations through two cycles or 360 of rotation of theshaft 26 may be summarized as follows:

From the top dead center, rotation of the shaft 26 through 180, causespower to be applied to the pistons 35 and 37 by burning gases in thecombustion chamber 14-19, driving the pistons outwardly. The connectingrods 48, 44, 46 and 50, under tension, transmit motion to the eccentrics26a, 26b, 26c and 26d, causing the crankshaft 26 to rotate. The outwardmovement of the pistons 35 and 37 transfers air from chambers 53 and 55through the check valves 64 and 71 into chambers 54 and 56, where theair is retained under pressure until the pistons 35 and 37 haveuncovered the exhaust ports 66 and 73, now uncover intake ports 64 and72, allowing air to pass from chambers 54 and 56 into cylinders 12 and13, effecting scavenging, and intake by suction ofair at atmosphericpressure into chambers 53 and 55, simultaneously with compression incombustion chamber 14-19.

As the pistons 35 and 37 approach the top dead center position, theysimultaneously compress air in the combustion chamber 14-19 and inchambers 54 and 56, the contents of which ultimately pass throughpassages 57 and 67 and check valves 60 and 68 into combustion chamber14-19, after fuel injection has been initiated. The secondarycompression introduces turbulen ce in the combustion chamber 14-19, tothereby cause more complete combustion.

The engine, as thus described, is a two-cycle engine, in which thenecessity for pressurized crankcase blowers or scavenging blowers iseliminated.

The engine may be constructed as described, or with any number ofduplicates of such mechanisms.

In the case of multiple cylinder engines, the cover plates 29 and 33will serve to close the ends of chambers 53 and 55, and in the caseof'multiple cylinder engines, these cover plates will be of sufficientlength to cover all of the cylinders of which the engine is constructed.

The cover plates 29 and 33 can also serve as mounting surfaces orsupports for locating and supporting the engine, and can also serve as aportion of a complete enclosure, which, in this configuration, may becomposed ofa total of six flat pieces, i.e., two cover plates 29 and 33,two end plates (not shown), and top and bottom plates (not shown), whichwould then, in effect, provide a complete oil-tight enclosure for theoperating mechanisms.

The mechanism, as described, can, with slight modification, also serveas an external combustion engine, a fluid power engine, or as acompressor.

Referring to the modification shown in FIGS. 10, 11 and 12, the engineis provided with passageways and 91, which extend through the walls ofthe cylinders 12-27 and 13-31, parallel to the axes of these cylinders,these passageways extending from the combus tion chamber 14-19 to thechambers 54 and 56 respectively.

The passageways 90 and 91 are respectively provided at the ends thereofadjacent the combustion chamber 14-19 with nozzles or jets 92 and. 93.

The cylinders 12 and 13 are also respectively provided with inlet ports94 and 95, which communicate with the passageways 90 and 91.

The heads 35a and 37a of the pistons 35 and 37 have secured therein theends of plungers 96 and 97 which extend into the passageways 90 and 91and are slidable in these passageways.

When the pistons 35 and 37 are: at the outer ends of their stroke, as inFIG. 8, fluid from any suitable source (not shown) enters the ports 94and 95 and the passageways 90 and 91. When the pistons return to theirtop dead center position, this fluid is injected by the plungers 96 and97 from the passageways through the nozzles or jets 92 and 93 and intothe combustion chamber 14-19.

The fluid injection means, as thus described, may also be employed toinject fuel, a cooling fluid, or a mixture of both, into the combustionchambers.

The nozzles or jets 92 and 93 are of a commercially available type ordesign which are normally closed and require pressure on the fluid(fuel, coolant or mixture), as by the plungers 96 and 97, to causepassage of the fluid through the nozzles. Nozzles or jets of this typeare described on pages 972 and 973 of Volume 38 of the 1973 Edition ofDiesel and Gas Turbine Worldwide Catalog.

It is to be understood that the forms of my invention, herewith shownand described, are to be taken as preferred examples of the same, andthat various changes may be made in the shape, size and arrangement ofparts thereof, without departing from the spirit of the invention or thescope of the subjoined claims.

Having thus described my invention, 1 claim:

1. In a two stroke engine including a housing having at least a pair ofaxially spaced cylinders extending therefrom in opposite directions andaxially aligned with each other, means communicating with said cylinderto define a combustion chamber, means introducing fuel into saidcombustion chamber, a piston mounted in each of said cylinders forsimultaneous reciprocating movement, said cylinders each communicatingat its respective outer end with a closed extension chamber of enlargeddiameter, and each of said pistons including a head of enlarged diametercomplementary to and reciprocally movable within said extension, meansin the closed ends of each of said extensions selectively admittingatmospheric air into said extension chamber of said cylinder uponmovement of said piston toward said combustion chamber, said portion ofsaid piston head of enlarged diameter including valve means foradmitting said atmospheric air in said extension chamber from theportion of said chamber at one side of said head to the portion of saidchamber at the opposite side of said head when said pistons are movedoutwardly in said cylinders away from said combustion chambercommunicating means, a crank shaft extending through the space betweensaid cylinders and provided with a pair of axially spaced eccentrics foreach piston, a piston pin extending diametrically through each of saidpistons, connecting rods interconnecting each of said eccentrics withsaid piston pins, means defining passageways extending within the wallsof said cylinders and said extensions parallel with the axis of thecylinders and extensions for selectively conducting air from saidchambers to said combustion chamber upon movement of said piston headstoward.

the combustion chamber, and'exhaust means associated with each of saidcylinders for discharging exhaust gases from said cylinders.

2. An engine as defined in claim 1 wherein said passageways are providedwith first and second valve means communicating with said combustionchamber. said first valve means being normally opened and closed uponthe predetermined advancement of said piston toward said combustionchamber, said second valve means being normally closed but operable tothe open position upon movement of said piston toward said combustionchamber after said first valve means is closed.

3. An engine, as defined in claim 1, wherein said passageways areprovided with first and second valve means communicating with saidcombustion chamber, said last-named valve means being normally closed,but operable to the open position upon movement of said pistons towardsaid combustion chamber after said first valve is closed.

4. An engine, as defined in claim 1, wherein said cylinders havepassageways therein extending parallel with the axes of the cylinders,said passageways extending to said combustion chamber, means foradmitting a fluid into said passageway, and means responsive to movementof said pistons for forcing said fluid from said passageways into saidcombustion chamber.

5. An engine, as defined in claim 4, wherein said lastnamed meanscomprises plungers mounted for slidable movement in said passageways.

1. In a two stroke engine including a housing having at least a pair ofaxially spaced cylinders extending therefrom in opposite directions andaxially aligned with each other, means communicating with said cylinderto define a combustion chamber, means introducing fuel into saidcombustion chamber, a piston mounted in each of said cylinders forsimultaneous reciprocating movement, said cylinders each communicatingat its respective outer end with a closed extension chamber of enlargeddiameter, and each of said pistons including a head of enlarged diametercomplementary to and reciprocally movable within said extension, meansin the closed ends of each of said extensions selectively admittingatmospheric air into said extension chamber of said cylinder uponmovement of said piston toward said combustion chamber, said portion ofsaid piston head of enlarged diameter including valve means foradmitting said atmospheric air in said extension chamber from theportion of said chamber at one side of said head to the portion of saidchamber at the opposite side of said head when said pistons are movedoutwardly in said cylinders away from said combustion chambercommunicating means, a crank shaft extending through the space betweensaid cylinders and provided with a pair of axially spaced eccentrics foreach piston, a piston pin extending diametrically through each of saidpistons, connecting rods interconnecting each of said eccentrics withsaid piston pins, means defining passageways extending within the wallsof said cylinders and said extensions parallel with the axis of thecylinders and extensions for selectively conducting air from saidchambers to said combustion chamber upon movement of said piston headstoward the combustion chamber, and exhaust means associated with each ofsaid cylinders for discharging exhaust gases from said cylinders.
 2. Anengine as defined in claim 1 wherein said passageways are provided withfirst and second valve means communicating with said combustion chamber,said first valve means being normally opened and closed upon thepredetermined advancement of said piston toward said combustion chamber,said second valve means being normally closed but operable to the openposition upon movement of said piston toward said combustion chamberafter said first valve means is closed.
 3. An engine, as defined inclaim 1, wherein said passageways are provided with first and secondvalve means communicating with said combustion chamber, said last-namedvalve means being normally closed, but operable to the open positionupon movement of said pistons toward said combustion chamber after saidfirst valve is closed.
 4. An engine, as defined in claim 1, wherein saidcylinders have passageways therein extending parallel with the axes ofthe cylinders, said passageways extending to said combustion chamber,means for admitting a fluid into said passageway, and means responsiveto movement of said pistons for forcing said fluid from said passagewaysinto said combustion chamber.
 5. An enginE, as defined in claim 4,wherein said last-named means comprises plungers mounted for slidablemovement in said passageways.